Battery cable connector



Dec. 23, 1952 J. R. GIER, JR

BATTERY CABLE CONNECTOR Filed Aug. 5, 1949 IN VEN TOR. JOHN P. 6715?, J5.

Patented Dec. 23, 1952 UNITED STATES PATENT OFFICE 8 Claims.

This invention relates to connectors, and more particularly to connectors or terminals employed to make electrical connection with the posts of storage batteries.

Storage batteries are low-voltage, high-current devices universally used as standard equipment for automotive service by the general public who give them very little care and considerable abuse but expect reliable performance from them. It is import-ant that the connections to the battery post remain clean and tight and that the joint have a very low ohmic resistance. Battery connectors or terminals are subject to mechanical dislodgment as well as to the corrosive effects of moisture and acids, and corrosion not only increases the resistance of the joint but weakens the terminals mechanically. The corrosive effects of the gases emanating from the battery cells precludes adoption of any structure that is mechanically complicated or employs delicate moving parts.

As a result of these and many other problems incident to the employment of storage batteries, the trade has universally adopted the well-known split clamp and bolt type of construction, which i is regarded as an expendable item because of its short life. Experience has shown that although such a clamp is relatively cheap to manufacture it leaves much to be desired relative to the solution of the problems briefly outlined above. i

(1) A terminal that provides a firm, resilient grip with the post, a grip that is mechanically strong and affords a permanent low resistance connection;

(2) A terminal that will accommodate post sizes normally encountered and yet will firmly and resiliently grip them all;

(3) A terminal that provides a grip of the character named in (1) above and wherein the gripping force is distributed over a large area of the post to avoid local deformation of the post; (4) A terminal that is readily applied without need for manipulation of fasteners such as bolts or the like, the terminal cannot freeze to the post and only ordinary pliers are needed to apply or remove it;

(5) A terminal that readily adapts itself to corrosion-protective shrouding, and may be applied and removed without disturbing the shrouding;

(6) A terminal, which although it has the above features and advantages is nevertheless as economical or more economical to manufacture than the standard clamp-type terminal now universally found in the trade, and which may reasonably be expected to last for the normal life of the car.

Briefly, in the broader aspects of the invention, the above features and advantages are obtained by making the terminal in the form of a tapered helical coil and by attaching a suitable cable connector to the coil, at a point more than one turn from either end, of the coil. By making the coil of spring wire having good electrical conductivity and of the proper section, the tabulated features and advantages are readily obtained. The coil resiliently grips posts of normal size variation and yet the gripping action is accumulative, that is, it is distributed over a substantial area of the post so that although the total gripping force is adequate, the local gripping force is not great enough to damage or deform the battery post. The coil has a wraparound action which assists in the gripping action of the coil when it is rotated about the post in at least one direction.

A terminal of the general nature described requires no bolts, screws or the like and so may be readily shrouded to prevent the deleterious effects of corrosion. I am aware that prior attempts have been made to provide terminals that resiliently grip the battery posts, but these have all been in the form of relatively stiff cantilevertype springs, which if made stiff enough to provide the desired grip have inadequate accommodation to post size variations and which if made flexible enough to accommodate these post variations will not firmly grip any but the largest of posts. Moreover, such extremely stiff spring devices would be very diflicult to apply and remove. Attempts have also been made to use rubber as the gripping medium, but rubber deteriorates rapidly in this service and relaxes its grip progressively with time.

. It is a feature of a preferred form of my in vention that once the terminal is applied any ex ternal torque or attempted rotation of the terminal about the post in either direction brings into play a wrapping action of the helical coil of wire and checks or snubs further rotation of the terminal. This is accomplished by mounting the cable connector at an intermediate point in the helix, there being at least one turn to each side of the connector. With this construction the portion of the coil to one side of the connector provides a wrapping action to resist rotation in one direction, and the portion of the coil to the other side of the connection functions in a like manner to resist rotation in the other direction. This form has an additional advantage in that the ends of the helix may be crossed wherebypliers or a similar tool may be applied to the ends of the coil to bring the ends together, expand the helix, and facilitate application and removal of the'terminal. This operation may be effected directly through the shroud, if one is fitted to the terminal.

The manner in which the aforesaid objects and advantages may be accomplished will be more clearly understood from. the following detailed descriptionof a preferred'embodiment of'the invention.

In the drawings;

Figs. 1 to 3 show the preferred embodiment whereinFig. 1 is a planview'withthe shroud sectioned; Fig. 2a side elevationtshowing the terminal applied to a battery post andwith the shroud sectioned; and, Fig. Sanend elevation withthe shroud sectioned.

A modification appears in Figs; 4 tov 6: wherein Fig. 4 is an end elevation with the device. applied tOa battery post; Fig. 5 is a side elevation of. the device; and; Fig. 6 is a planview with the cable removed and. parts of the cable connecting, eye brokenaway to show the direction of wind of the coils.

Referring toFigs. ltov 3., it can be seen that I providev a terminalor connector T',. which has soldered or. otherwise fastened thereto. the. usual battery cableC, and the. terminalmay be. enclosed byv a. shroud S ofrubber-like material. In the preferred-form the terminalT includ'esa single helicalcoil le-of spring wire preferably wound with a slight taper so as to correspond in profile to the conventional. battery post. I prefer that thehelical coil be formed. of a metal having good electrical. conductivity and relatively high resistance to corrosion. Suitable materials for the coil may be selected from the commercial spring brasses and bronzes. In order to increase the torsional stiffness of the coil. I prefer. that the w-iregoing to makeup the. helix. be made Of..fl2,t-

tened. round wire,.although insome applications wire of circular section may prove satisfactory. In order toprovide for ready application andremoral. of. the connector theendsof the helix are crossed as shown at H and I2 and they may be bent axially to provide gripping surfaces for receptionof tools such as pliersor. the like.

The cable may be connected directly to. the helix, or preferably a cable connector in the form of a sleevev or socket i3v may be employed; The sleeve is flattened as at M and soldered or welded to one of the coils of the helix. It is an important feature of the preferred form of the invention that thecable or the connecting sleeve, if such is employed, be attached to the helix at a point spaced at least one turn from each end of the coil. For example, in the preferred construction the helix includes three complete turns and the cable socket is connected to the midturn. With this construction it will be. noted that the portion of the helix above the cable will tend to wrap around or snub against the post and fifecti-vely prevent relative rotation of the parts in one direction, whereas the other portion of helix acts to snub rotation in the other direction. Although I prefer that an odd number of turns be provided with the cable connecting to the midturn, in the broader aspects of the invention this is not necessary so long as the cable is connected at 9. point wherein it is spaced from the nearest end of the helix by more than one turn. The resilient gripping force is distributed substantially over the entire length of'the battery. post so that the unit load at anypoint is not high enough to damage the post, and yet the loading is accumulative so that the total gripping force is adequate to firmly retainthe terminal on the post and to maintain a low resistance electrical connection.

The construction just described readily adapts itself to incorporation of a shroud S, which is preferably molded of a flexible, acid-proof material such-as natural or synthetic rubber. The shroud is formed or molded to fit snugly about the terminal. at its junction with the cable, and is formed .with an opening [5 adapted to receive and make sealing, engagement with the. battery post P and exclude gases and moisture from the interior. of the shroud. The shroud may be filled with .an inert material 16 such as petroleumjelly toprotect the parts. and assist in the exclusion of corrosion-producing fluids.

Depending upon the nature of the service and the absence or presence of the shroud, .I- may apply to the terminal-by dipping or plating a thin coating of acid-resistant metal suchas lead; or a non-metallic coating such as rubber except on the post contact surface. The. coating is thin enough .so thatitdoes notinterfere with the resilient action. of the helix.

In. operation,.the opposed radially extending ends I-] and. 12 of the helix are gripped and brought together, thereby expanding the helix slightly so that itmay be readily slipped, over the battery post. Once the terminal ends are. released the coil resiliently grips the post throughout the length of the helix and, as previously described, remains securely attached until the endsv H and I2v are againforced. toward one another. Noseparate manipulation of the shroudis required because the terminals II and I2 can be readily manipulated through. the shroud.

In the form shown in Figs. 4 to 6, the terminal T1. includes a double helix. The first helix. 20 is of double pitch and is intertwined with the second helix 2|, alsoof double pitch. The helix 20. has at its upper end an eye 22. for reception of the bared end of the battery cable C and helix 2| has. a similar eye 23 spaced from eye 22'by approximately the diameter of the battery post P. As' best seeninFig. 5; the direction of wind. of eachhelix is the same. In accordance with theprinciples discussed, the terminal. and the. cable end may be protected by a shroud S1 having a.post-receiving opening 24. As mentioned above, petroleum jelly or the like may act within the terminal to agument the. corrosion-resistance properties of the device.

In operation the terminal T1 is applied to the post and a simultaneously downward pressure anda slight twisting action in the direction of the wind of the coils are effected. frictionally expands somewhat the coils so that they maybe readily passed over the post. When the terminal i'sreleased the coils resiliently grip the post much in the manner described above, and the firm resilient grip of the coils is such as to retain. the terminal in good electrical contact with the post under ordinary conditions.

When it is desired to remove the terminal it is again twisted in the direction of wind and merely lifted, whereupon it may be readily removed from the battery.

Having completed a detail description of my invention, it can be seen that I have produced a device which may be economically manufactured so that it is competitive with the conventional strap-like clamps now employed in the trade, yet the device has numerous advantages and new results not obtainable by the standard commercial clamps or by any other clamps found in the art. The grip against the post is firm enough to withstand all forces normally encountered and yet it is an accumulative grip so that at no point is the post unnecessarily deformed, and the device will accommodate a range of sizes of posts. Protective shrouding can be applied readily and the terminal connected to and removed from the battery without disturbing the shrouding.

These and other advantages will be apparent and have been described, and although a preferred embodiment of the invention has been described so that those skilled in the art may practice the invention, applicant contemplates that various changes and modifications may be made without departing from the essence of the invention. Accordingly, it is intended that the appended claims and not the aforesaid embodiments be determinative of the scope of my in vention.

What is claimed is:

1. A battery terminal for eiiectively gripping and accommodating a battery post comprising an axially internally tapered helical coil of wirelike spring material having good electrical conductivity, each turn of which is of substantially smaller axial dimension than the post, said coil including an odd number of turns, no less than three, a cable extending from the midturn of said coil, whereby substantially half of the coil is tightened against the post when the terminal is rotated about the post in either direction,

the ends of said wire-like material extending radially past the coil and crossing so that the coil is expanded. when its ends are forced toward one another.

2. A battery terminal for effectively gripping and accommodating a battery post formed of relatively soft material comprising an axially internally tapered helical coil of wire-like spring material, said wire being of oblong section and having good electrical conductivity, each turn of said wire being of substantially smaller axial dimension than the post, said coil including an odd number of turns, no less than three, a cable extending from the midturn of said coil, whereby substantially half of the coil is tightened against the post when the terminal is rotated about the post in either direction, the ends of said wirelike material extending radially past the coil and crossing so that the coil is expanded when its ends are forced toward one another.

3. A battery terminal for effectively gripping and accommodating a battery post comprising a helical coil of wire-like spring material having good electrical conductivity, each turn of which is of substantially smaller axial dimension than the post, said coil including an odd number of turns, no less than three, a cable extending from the midturn of said coil, whereby substantially half of the coil is tightened against the post when the terminal is rotated about the post in either direction, the ends of said wire-like material extending radially past the coil and crossing so that the coil is expanded when its ends are forced toward one another.

' 4. A battery terminal for effectively gripping and accommodating a battery post formed of relatively soft material comprising an axially internally tapered helical coil of wire-like spring material having good electrical conductivity, each turn of which is of substantially smaller axial dimension that the post, said coil including three or more turns, a cable extending from said coil and spaced more than one turn from either end of said coil, whereby a substantial portion of the coil is tightened against the post when the terminal is rotated about the post in either direction, the ends of said wire-like material extending radially past the coil and crossing so that the coil is expanded when its ends are forced toward one another.

5. A battery terminal for effectively gripping and accommodating a battery post formed of relatively soft material comprising an axially internally tapered helical coil of wire-like spring material having good electrical conductivity, each turn of which is of substantially smaller axial dimension than the post, said coil including three or more turns, a cable extending from said coil and spaced more than one turn from either end of said coil, whereby a substantial portion of the coil is tightened against the post when the terminal is rotated about the post in either direc tion, the ends of said wire-like material extending radially past the coil and crossing so that the coil is expanded when its ends are forced toward one another, and a shroud of rubber-like material surrounding said terminal and including an opening for reception of a battery post.

6. A battery terminal for effectively gripping and accommodating a battery post formed of rela'tively soft material comprising an axially in ternally tapered helical coil of wire-like spring material having good electrical conductivity, each turn of which is of substantially smaller axial dimension than the post, said coil including an odd number of turns, no less than three, a cable extending from the midturn of said coil, whereby substantially half of the coil is tightened against the post when the terminal is rotated about the post in either direction, the ends of said wire-like material extending radially from the coil and crossing so that the coil is expanded when its ends are forced toward one another, and a shroud of rubber-like material surrounding said terminal and including an opening for closely fitting the battery post, said coil ends being manipulable through the shroud for application and removal of the terminal.

7. A quick attachable self-tightening electrical connector comprising a helical coil of resilient conductive metal, a cable rigidly connected to a portion of one turn of said coil, said coil extending for more than one turn from each side of the zone of cable attachment, said connector resiliently gripping a post and resisting rotation on said post in both directions, the ends of said coil terminating adjacent one another and hav- 7 cn-.said;posti imboth. directions, the ends. 01 said coil tenninatingadjacentone another, and means projecting from the ends: of. saidv coil and: diverging therefmmfoztzreeeption of. meansfor expandingz. the; coil, the total number of turns represented by saidcoil; and. projecting; means exceeding: three, wherebysaidcoilis expanded by bringing-thettezminal portions of said projectingmeans together.

JOHN R. GIER, JR.

REFERENCES CIT-ED The following references are of. recordin the me of this" patent:

8 UNITEDSTATES PATENTS Number 10 Number Name Date Munyan Dec; 29, 1908 Gould Mar.- 30, 1909 Churchill Sept; 7", 1915 Kennington Oct. 2; 1928 Rowe Mar. 3:, 1936 FOREIGN PATENTS Country Date England of- 1911 Australia Apr; 6, 1934 France Aug. 31, 1920 

